Field of the Invention
This invention relates to underground valves, such as utility valves and, more particularly, to a conduit assembly through which above ground access can be gained to a valve.
Background Art
Underground valves are used to selectively control utility supply, such as water, to individual residences and businesses. Each valve is typically situated several feet underground and is accessed through a vertical conduit assembly. In one known form, the upper end of the conduit assembly is closed by a cap with a separable plug that is threaded into place. The plug is separated to produce an entry opening to a passage extending downwardly to the valve. The plug is provided with a fitting to be engaged by a special tool, which thereby allows a level of control of access to the valve.
Existing conduit assemblies take a number of different forms. In one form, a cast housing, with an inverted cup shape, is placed over the valve and straddles the supply line and valve. The housing continues upwardly into a conduit, with a length selected so that the cap on the conduit is flush with grade.
In an alternative design, a conduit assembly has a fitting that is threaded directly to the underground valve. The conduit assembly defines a passage that extends continuously from the valve to an upper access opening.
With both of the above designs, elongate tools are directed from above ground through the conduit assembly passages to engage actuators on the valves. The tools control turning of the actuators in opposite directions to selectively open and close the valves.
Existing designs have some inherent problems, some of which are aggravated as the parts thereof corrode and/or are otherwise affected by environmental conditions.
One such problem involves alignment of the conduit passage with the valve actuator. This is an issue primarily with systems utilizing a straddling housing that may be permitted to shift relative to a valve to the point that the valve actuator becomes inaccessible through the conduit assembly passage. This condition may result from a defective installation, shifting from frost, etc. If valve access is required, the ground may have to be removed to allow a worker to get into close proximity to the valve to effect operation thereof and/or to re-install the conduit assembly.
Another problem is a result of the manner in which the upper cap and plug, that is a part thereof, are constructed. Typically, the plug is made from brass so that it is not prone to rusting. The threads on the brass plug mate with threads on another part of the cap, typically made from a dissimilar metal. That other metal is generally prone to rusting or corroding, which could cause the threads to bind, thereby inhibiting turning of the plug for separation. It may become necessary to exert a substantial torque upon the plug to effect separation thereof. This torque may cause another part of the conduit assembly to turn. Depending upon the particular construction, this turning may inflict damage upon the conduit assembly, the housing at the bottom thereof, the valve, and/or the supply line. This again is particularly a problem with systems utilizing a straddling housing that may be turned relative to the valve and supporting line in a manner that inflicts damage thereto.
When this condition exists, the individual seeking to operate the valve has the option of either taking exceptional steps to avoid turning of any other part of the conduit assembly associated with the plug, or gambling that the plug will break free before the failure of any other part of the system under a large turning torque.
The former option represents a significant inconvenience, particularly when utilities budget very little time for their workers to effect access. The latter can have significant consequences, and in a worst case may necessitate a time-consuming repair that could involve replacement of one or more system parts. In an extreme case, the valve itself may have to be accessed, which involves digging around the conduit assembly to create an access opening wide enough to allow a worker to repair, or remove and replace, the damaged structure, potentially including the valve.
In the event the valve itself must be replaced, the utility may have to utilize an upstream shutoff that could inconvenience not only the immediately affected entity, but any entity supplied through an interconnected conduit network downstream of the shutoff.
The above problems may be aggravated by temperature and other weather conditions. For example, rain followed by freezing temperatures may further lock the system components and make separation of the access plug even more difficult.
Another problem that has existed is that it is difficult to engage the valve operating tool with the underground actuator, particularly with conduit assemblies having a substantial vertical length. To address this problem, it is known to utilize extension rods. Such rods have connecting ends attached to the valve actuator and a spaced actuating end that is engageable by an appropriate tool operated from above ground.
Even with an extension rod incorporated into the system, it may be difficult for a user to effect engagement of the tool with the actuating end of the extension rod. To facilitate this process, it is known to provide a number of bends in the extension rod to keep the extension rod generally centered within the conduit assembly. However, incorporating bends adequate to substantially center the extension rod could result in interference between the extension rod and conduit assembly as the extension rod is turned around a vertical axis. Thus, this problem has persisted in spite of past efforts to address it.
A still further problem with conventional systems is that they are prone to tampering by unauthorized individuals. Systems of the above type are designed with a balance between allowing workers reasonable access and precluding unauthorized access. Generally, a casual observer can determine how a cap is installed. Often, without exceptional effort, an unauthorized person may ascertain the easiest way to remove the cap and thereafter tamper with the underground valve or potentially obstruct future operation of the valve.
In spite of these inherent deficiencies with existing systems, the industry has continued to use conventional designs. The industry continues to seek out alternative designs that are economically feasible, while being reliable in terms of their operation, regardless of environmental conditions.